CONTROLLED//PROPIN//BASIC 

CVB-DAT-5116.02 Page 1 of 2 

Controlled by: APHIS Center for Veterinary Biologics, 515-337-6100 

United States Department of Agriculture

Animal and Plant Health Inspection Service

Center for Veterinary Biologics

P. O. Box 844

Ames, IA 50010

1. Reagent Name: Clostridium sordellii Toxin 

2. Strain or Source: Not Applicable 

3. Lot Number: IRP 675 

4. Fill Date: November 7, 2019 

5. Expiration Date: February 28, 2029 

6. Intended Use: IRP 675 serves as the standard toxin when conducting C. sordellii toxinneutralization (TN) tests in mice. 

7. Instructions for Use: C. sordellii toxin IRP 675 diluted 1:10 is considered the standard 

toxin dilution when conducting TN tests in mice as outlined in title 9, Code of Federal

Regulations (9 CFR), part 113.109. The standard toxin dilution is prepared by adding 1.0 mL of 

well mixed IRP 675 to 9.0 mL of sterile peptone diluent (1.0% peptone, 0.25% sodium chloride, 

pH 7.2). A volume of 0.5 mL of the toxin diluted 1:10 and 0.5 mL of diluent represents 1.0 Lo

toxin dose. A volume of 0.8 mL of the toxin diluted 1:10 and 0.2 mL of diluent represents 1.0 L+ 

dose.

8. Test of Reagent: Determination of test dose of toxin – The Lo and L+ doses were 

established by injecting 16 to 20 gram mice intravenously with 0.2 mL of varying amounts of 

IRP 675 combined with 1.0 mL of C. sordellii antitoxin IRP 501 containing 1.0 antitoxin unit per 

mL (AU/mL). The Lo and L+ doses were confirmed by injecting 16 to 20 gram mice 

intravenously with 0.2 mL of varying amounts of IRP 675 combined with 1.0 mL of 

International Antitoxin containing 1.0 IU/mL. 

The Lo dose for the C. sordellii TN test is the largest quantity of toxin which can be mixed with 

1.0 unit of antitoxin and not cause death in injected mice within 72 hours. The L+ dose for the C. 

sordellii TN test is the smallest amount of toxin which can be mixed with 1.0 unit of antitoxin 

and cause death in at least 80% of injected mice within 72 hours. 

Precautions: This reagent does not present a hazard to laboratory personnel who manipulate the 

serum provided sound fundamental laboratory practices are followed. 
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CVB-DAT-5116.02 Page 2 of 2 

Controlled by: APHIS Center for Veterinary Biologics, 515-337-6100 

Determination of LD50 – White Swiss mice weighing 16-20 g were injected intravenously with 

0.2 mL of IRP 675 diluted in peptone diluent. The toxin was found to contain 104.5 lethal dose 

fifty (LD50) per 0.2 mL.

Sterility test – The toxin was tested for sterility and found to be free of viable bacteria and fungi 

according to procedures outlined in 9 CFR 113.26. 

9. Container Size, Type, Weight, or Volume: 4-mL glass vials containing 1.3 mL of toxin 

10. Storage Conditions: Store at -50° to -90°C. 

11. CVB Technical Contact: Bacteriology Section, Center for Veterinary Biologics, 

(515) 337-6100 or FAX (515) 337-7673 

12. Origin and Passage History: C. sordellii culture No. 7502, used to produce IRP 675, 

was obtained September 16, 1968, from Montana State University, Bozeman, Montana. The 

number of passages is unknown. 

13. Method of Preparation: Culture 7502-1-11 was grown in dialysis membranes with a 

molecular weight cutoff range from 12,000 to 14,000 daltons. The membranes were filled with 

0.15 M phosphate buffered saline, pH 7.4, and suspended in 1-liter trypsinizing flasks containing 

media consisting of Brain Heart Infusion Broth. Actively growing culture was aseptically added 

to the inside of the dialysis membranes and incubated at 35oC for 50 hours in an anaerobic glove 

box containing 85% nitrogen (N), 10% hydrogen (H), and 5% carbon dioxide (CO). The culture

was centrifuged at 10,000 x g for 60 minutes. The culture supernatant was passed through a 

sterile Pall VacuCap 90 PF filter unit containing a 0.8/0.2- Supor® membrane. 

14. Other: None

Reagent orders and feedback should be sent including phone number to the following email 

address, VS.DB.CVB.Reagent.Requests@usda.gov.

Reagent orders forms (APHIS Form 2018) can be found on the CVB website.